1. Field of the Invention
The present invention refers to a crash box applicable in the automotive field and in particular usable as sacrificial element in a bumper structure of a motor vehicle.
2. Description of the Related Art
Typically a crash box is able to absorb a portion of kinetic energy during a crash of a motor vehicle against an obstacle fixed or mobile.
In particular the present invention is referred to a crash box of polymeric type, of the type realized in particular through injection molding and having a substantially alveolar structure, in such a way to have a good impact strength and high rigidity, accompanied with a reduced weight.
Each crash box shows a first frontal extremity which stand for first the crash, and a second rear extremity, which is constrained to a frame of the vehicle.
Each crash box is in fact designed for having in the case of crash a permanent plastic deformation and a programmed collapse starting from a frontal portion towards a second rear portion of the same determining consequently a plurality of folding starting from said frontal portion towards said second rear portion.
In this way each crash box is able to absorb and to progressively dissipate a portion of kinetic energy through plastic deformation and by means of the propagation of said plurality of folding, maintaining a reduced volume and weight.
A disadvantage of the polymeric crash boxes is that, in the case of a crash force angled respect to the first frontal extremity, it determines a bending moment which compromise the stability and, often determines a sudden failure or a deformation of the rear extremity of the crash boxes, compromising their correct working during the same crash.
Another analogue disadvantage is that in the case of a failure of a support element constrained to said second rear extremity, it determines an intensification of the stresses on said second rear extremity compromising the functionality of the crash box.
This because also in this case the plurality of folding start from said second rear extremity.